Genetic evidence for panmixia of Japanese eel (Anguilla japonica) populations in China.

The Japanese eel population has dramatically declined since the 1970s. In order to conserve this species, the background genetic structure affecting these populations should be well documented. Previous genetic studies of this species have produced seemingly conflicting results, ranging from no detectable heterogeneity to small, but statistically significant variance. This study investigates the population structure of Japanese glass eels collected from 10 localities in China in 2009 using a mitochondrial DNA (mtDNA) control region and 19 polymorphic microsatellite loci. Results revealed evidence of low genetic differentiation using both mtDNA (FST = 0.001, P = 0.291) and microsatellite data (FST = 0.003, P = 0.008). Pairwise F-statistic values generated from mtDNA and microsatellite DNA were similar, showing little evidence of significant genetic differentiation. The minimum spanning haplotype network constructed using mtDNA control regions produced no clear phylogeographic structure. The Mantel test revealed no significant correlation with distances for both mtDNA and microsatellite DNA. Therefore, our results suggest a panmictic population of Japanese eels in China, which should be conserved as a single management unit.